According to earlier scientific research, orca may use dedicated herding calls on herring, which can lead to schooling or – if the calls have the right frequency – to vibrating swimbladders that hinder the fish to escape. One interesting question was whether orca adapt their calls specifically to spawning herring as opposed to overwintering herring.
In a scientific study published now by Filipa I.P. Samarra (Marine Research Institute, Iceland & University of St. Andrews, UK) in the journal Behavioural Processes, orca were observed and their calls recorded over several years in spawning as well as overwintering grounds of Icelandic herring. Interestingly, the study finds that “feeding killer whales produce herding calls when feeding upon both spawning and overwintering herring. These results suggest that herding calls increase foraging efficiency by herding herring, regardless of herring school density, and likely represent a key element of the feeding techniques of at least some whales.”
The author also notes that “calls in the whales’ repertoire, such as the herding call, could be culturally transmitted, and differences in call characteristics could be the result of cultural drift.”